Probiotic micro-organisms are micro-organisms which beneficially affect a host by improving its intestinal microbial balance. In general, it is believed that these bacteria inhibit or influence the growth and/or metabolism of pathogenic bacteria in the intestinal tract. It is also assumed that via probiotic micro-organisms the immune function of the host is activated. For this reason, there have been many different approaches to include probiotic micro-organisms into food-stuffs.
WO98/10666 (SOCIETE DES PRODUITS NESTLE S.A.) discloses a process for manufacturing a dehydrated food composition containing live probiotic acid bacteria, in which a food composition and a culture of probiotic lactic acid bacteria sensitive to oxygen are sprayed conjointly under a stream of hot air.
EP0862863 (SOCIETE DES PRODUITS NESTLE S.A.) discloses a dried, ready-to-eat cereal product comprising a gelatinised starch matrix which includes a coating or filling containing a probiotic microorganism.
U.S. Pat. No. 4,943,437 (AB MEDIPHARM) discloses a process for supply of biologically active materials to base food materials, in which the biologically active material is slurried in an inert carrier, where it is insoluble, to form a homogeneous suspension, after which the suspension is applied to the base material.
GB2205476 (UNILEVER) discloses a supported bacterial composition comprising an inert subdivided support, which is flour, and an aqueous suspension of viable microflora. This mixture is then dried and is suitable as inoculum of lactic acid bacteria for the preparation of sour-dough bread.
The incorporation of probiotic micro-organisms (hereinafter “probiotics”) into foodstuff, however, entails a number of difficulties. One first goal to reach is to have an adequate number of cfu (colony forming unit) per day. If the concentration of the probiotics in the product does not exceed a certain threshold value, the beneficial effect is not provided. Hence, starting from the observation that that an effective dose is in the range of 109 cfu per human per day, and, supposing, that the consumer has to take them within his/her daily intake, it is the objective to deliver this amount of cfu within one to three servings.
Hitherto, the approach has been to use probiotics that have been dried, either per se or together with a supporting substance. Hence, after fermentation in a suitable medium, the probiotics are usually concentrated, for example by centrifugation or filtration, and are then dried by spray-drying, fluidized-bed drying or freeze-drying. From the drying process, another, serious problem arises. That is, the probiotics sustain substantial loss in the range of 60, more frequently 90 to 99% of cfu depending on the applied technology, unless special measurements are taken. It goes without saying that these drying steps are very energy-expensive. But the high temperature drying process has other disadvantages. It may destroy or impair metabolites that are present in the probiotics them-selves or in the fermented medium where they were cultivated. Such metabolites may therefore lose their beneficial effects. The disadvantage of a concentration step, likewise, is the loss of metabolites that were present in the fermented medium.
The powder obtained by drying may then be applied to the desired food-product. According to the above cited EP0862863, for example, the dried probiotics are mixed with a liquid carrier substance, which is either oil, water or a protein digest. Then this substance is sprayed onto the food-product.
Due to the need of a relatively high number of cfu within a single meal and the high losses during drying, it is a problem to have a food-product with an effective number of cfu. A further problem, also addressed in the above cited references, is the long term stability of the probiotics on the food-product, i.e. the food-product with the probiotics has to be shelf stable at ambient temperature. Another concern is the viability of the probiotics in the stomach and the intestine. The probiotics must be sufficiently resistant to the acid environment in the stomach and to the bile acids in order to successfully colonize the intestine. Furthermore, the food-product comprising probiotics must be palatable to the consumer. There is a need to apply probiotics to a food-product without notably influencing its organoleptic properties.
It is indeed a problem to obtain only little or even no changes in flavor, appearance and texture of a finished product containing probiotics with respect to the same product without probiotics.
The present invention addresses the problems mentioned.